1. Field of the Invention
This invention relates to tools, and more particularly to a decoupling tool for unlocking a fifth wheel assembly to allow decoupling of a trailer from a tractor.
2. Description of the Prior Art
In large highway transport vehicles of the tractor-trailer type, an assembly commonly referred to as a fifth wheel is mounted on the rear of the tractor for demountably coupling the trailer to the tractor. The fifth wheel assembly is a device which lockably receives a kingpin dependingly carried on the trailer and allows the trailer to pivotably turn relative to the tractor.
The fifth wheel assemblies, although varying somewhat from one manufacturer to another, are all basically the same with regard to their configuration and operation. In general, fifth wheel assemblies will automatically lock the trailer's kingpin in place when the tractor is backed up so as to move the fifth wheel into engagement with the kingpin. Fifth wheel assemblies are provided with a release, or unlocking handle which, in most cases, must be manually pulled so that decoupling of the trailer from the tractor can be accomplished.
As is well known in the art, pulling the release handle to unlock the fifth wheel assembly can be a very dirty job and oftentimes it is a difficult thing to accomplish.
The pivotable operation of the fifth wheel assemblies require that they be covered with grease for proper operation, and they are almost constantly being subjected to mud, slush, snow, road tar and other contaminants due to their physical location adjacent the rear wheels of the tractor. The grease and road contamination, both on the fifth wheel itself and the surrounding areas such as the tractor's wheels and frame and the underside of the trailer, make this a less than ideal place into which the vehicle's operator must reach or crawl in order to pull the fifth wheel release handle.
When both the trailer and the tractor are on a substantially level, or evenly sloping surface, manual pulling of the fifth wheel release handle is usually an easy thing to accomplish. However, if the angular rotation of the trailer about its longitudinal axis differs from the angular rotation of the tractor about its longitudinal axis, the locking mechanism of the fifth wheel assembly can be subjected to binding forces which makes it difficult, if not impossible, for anyone to pull the release handle. Such binding is not an infrequent occurrence, and when it does occur the vehicle's operator has heretofore been required to reposition the tractor and trailer until he achieves a substantially aligned disposition therebetween. Sometimes, properly aligned disposition of the tractor and trailer can be achieved with a single repositioning maneuver, and sometimes the operator will spend considerable time before he achieves the required alignment.
This repositioning of the tractor and trailer to relieve binding of the fifth wheel can be a very time consuming and costly operation, which, in conjunction with the inherently dirty area, can be very frustrating to the operator of the vehicle, and costly to him with regard to ruined clothing.
To the best of my knowledge, no device has been developed or suggested for assisting the operator in such tractor-trailer decoupling operations. Therefore, a need exists for a new and useful decoupling tool which facilitates the unlocking of fifth wheel assemblies.